Do Breast Implants Affect Breast Cancer Risk?

The number of women choosing surgical breast implants for cosmetic reasons is skyrocketing, leading researchers and clinicians to wonder whether the implants affect the results of mammography screening and thereby increase a woman's risk of dying from breast cancer.

The implants appear as a solid white mass on radiographic film, obscuring some breast tissue.

In the first major effort to address this question, researchers -- led by UCSF Comprehensive Cancer Center member Karla Kerlikowske, MD, and statistician Diana Miglioretti, PhD, from the Group Health Cooperative's Center for Health Studies in Seattle -- used an extensive database containing mammogram results from 1.7 million women. The mammograms were collected from seven regional mammography registries across the United States. The researchers found 137 women with implants who had breast cancer, and matched them by age and other characteristics with 685 women without implants who had breast cancer.

The researchers found that screening mammography failed to reveal 55 percent of breast cancers in women with implants, versus 37 percent among women without implants (JAMA, January 28, 2004, pp. 442-450). Although mammography performed worse for women with implants, both failure rates are high. This is because women with implants are younger on average than the greater population of women who undergo screening. Younger women have denser breasts -- making tumors harder to see on mammograms -- and tumors that occur in younger women commonly grow faster and may become diagnosed clinically after a normal result on a screening mammography examination.